The New York Times has an interesting update on drug courts. Here's the money quote:
"[R]ecidivism rates for participants are reduced by about 10 ...

"[R]ecidivism rates for participants are reduced by about 10 percent to 20 percent, depending upon the quality of the judges and treatment programs, said John Roman, a researcher at the Urban Institute, based on a recent study."

Sounds great, yes? UCLA's Mark Kleiman isn't so sure:

"But some scholars, like Mark A. R. Kleiman, director of the Drug Policy Analysis Program at the University of California, Los Angeles, remain skeptical about the potential and the achievements. He suggests, for example, that success rates of some courts may be inflated because they take in offenders who are not addicted and entered this track only to avoid prison. Dr. Kleiman advocates a slimmed-down system that does not initially require costly treatment, as drug courts do, but simply demands that offenders stop using drugs, with the penalty of short stays in jail when they fail urine tests. Such an approach has shown promise with methamphetamine users in Hawaii, he said, and because it is far cheaper, it can be applied to far more offenders."